This Resource Application requests the support necessary to make the Albany 1.2 MV high voltage electron microscope (HVEM) available to outside users and to maintain the Core Research program (where not already separately supported). This HVEM is the only one in the East which is the region of the country with the highest concentration of biological electron microscopists. The penetrating power of the HVEM enables whole cells to be viewed in depth stereoscopically either as a small series of thick sections or as critical-point-dried whose cell mounts. The medium voltage (100 kV) EM is mainly restricted to two dimensional viewing of thin slices about 1/300th of a cell in thickness. The HVEM simultaneously increases the speed of examination of cell structure and its reliability of statistical sampling. While the bulk of routine work involves stereoscopy of thick sections and whole cell mounts for a wide variety of cell types, the Albany facility has two unique HVEM features: (1) digital 3-D reconstruction of tilted thick specimens (tomography) and (2) extra high sensitivity microprobe element analysis of biological specimens. The latter includes x-ray analysis of thick specimens and electron energy loss spectroscopy (EELS) of wet specimens contained in a differentially pumped environmental chamber. Additional capabilities include rapid autoradiography of thick sections and high resolution dark field observation of unstained specimens. An additional resource capability is being developed to examine the mitotic spindle apparatus in a wide variety of plants and animals.